Climate-induced variability in South Atlantic wave direction over the past three millennia.

Autor: Silva AP; Graduate Program in Oceanography, Federal University of Santa Catarina, Box 476, Florianópolis, SC, 88040-900, Brazil. ana.dasilva@griffithuni.edu.au.; Griffith Centre for Coastal Management (GCCM), Building G51, Griffith University, Gold Coast, QLD, 4215, Australia. ana.dasilva@griffithuni.edu.au., Klein AHF; Graduate Program in Oceanography, Federal University of Santa Catarina, Box 476, Florianópolis, SC, 88040-900, Brazil., Fetter-Filho AFH; Graduate Program in Oceanography, Federal University of Santa Catarina, Box 476, Florianópolis, SC, 88040-900, Brazil., Hein CJ; Virginia Institute of Marine Science, William & Mary, P.O. Box 1346, Gloucester Point, VA, 23062, USA., Méndez FJ; Department of Sciences and Techniques in Water and Environment, Cantabria University, Santander, Spain., Broggio MF; Graduate Program in Oceanography, Federal University of Santa Catarina, Box 476, Florianópolis, SC, 88040-900, Brazil., Dalinghaus C; Graduate Program in Oceanography, Federal University of Santa Catarina, Box 476, Florianópolis, SC, 88040-900, Brazil.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2020 Oct 29; Vol. 10 (1), pp. 18553. Date of Electronic Publication: 2020 Oct 29.
DOI: 10.1038/s41598-020-75265-5
Abstrakt: Through alteration of wave-generating atmospheric systems, global climate changes play a fundamental role in regional wave climate. However, long-term wave-climate cycles and their associated forcing mechanisms remain poorly constrained, in part due to a relative dearth of highly resolved archives. Here we use the morphology of former shorelines preserved in beach-foredune ridges (BFR) within a protected embayment to reconstruct changes in predominant wave directions in the Subtropical South Atlantic during the last ~ 3000 years. These analyses reveal multi-centennial cycles of oscillation in predominant wave direction in accordance with stronger (weaker) South Atlantic mid- to high-latitudes mean sea-level pressure gradient and zonal westerly winds, favouring wave generation zones in higher (lower) latitudes and consequent southerly (easterly) wave components. We identify the Southern Annular Mode as the primary climate driver responsible for these changes. Long-term variations in interhemispheric surface temperature anomalies coexist with oscillations in wave direction, which indicates the influence of temperature-driven atmospheric teleconnections on wave-generation cycles. These results provide a novel geomorphic proxy for paleoenvironmental reconstructions and present new insights into the role of global multi-decadal to multi-centennial climate variability in controlling coastal-ocean wave climate.
Databáze: MEDLINE
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